Key to Wisconsin Caltha

Authors: Theodore S. Cochrane & John G. Zaborsky

• 1a.Stems erect, or sprawling with age, not rooting at the nodes; flowers bright yellow; sepals 10–25 mm long C. palustris

• 1b.Stems creeping or floating, rooting at the nodes; flowers white; sepals 4–8 mm long C. natans